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Conversion of forestland to intensively managed agricultural land occurs worldwide and can increase soil nitrous oxide (N

Torreya grandis (Torreya grandis cv. Merrillii) is a unique nut tree species in China. Currently, researches on Torreya grandis focus on nuts quality and yield, while few works are related to the soil quality of Torreya grandis plantation. In this study, the typical Torreya grandis production areas of Zhuji, Shengzhou, Keqiao and Dongyang cities along the Kuaiji Mountain were selected. A total of 121 topsoil samples (0-20 cm) were collected based on a grid of 1 km × 1 km. The results indicated that the average concentrations of Cd, Cr, Cu, As, Ni and Pb in soils were 0.12, 49.01, 27.95, 14.28, 26.97 and 40.28 mg kg

Phytoliths are siliceous substances that are abundant within intercellular spaces and inside cells of numerous types of plants. During the formation of phytoliths, between 0.2 and 5.8% of organic carbon (C) can be occluded within the phytoliths. Phytolith-occluded C (PhytOC) in terrestrial ecosystems is a stable C sink and can be distributed in organic matter that is not strongly associated with soil minerals (LFOM) or that is strongly associated with mineral particles (forming organo-mineral complexes) (HFOM). We (1) investigated the impact of plantation age and soil depth on the size of the PhytOC pool and its distribution in soil physical fractions in Moso bamboo (Phyllostachys pubescens) forests; and (2) explore the relationship among phytoliths and PhytOC (and their fractions) concentrations and the soil properties. We used a chronosequence approach by sampling 5-, 10-, 20-, 50-, and 100-year-old Moso bamboo stands to examine the effect of plantation age on PhytOC storage and its distribution between the LFOM and HFOM pools. Our results showed that PhytOC concentration and the concentration of PhytOC in LFOM and HFOM increased with increasing stand age in the topsoil (0–30 cm) but not in the subsoil (30–100 cm). Long-term planting of Moso bamboo forests increased the soil PhytOC pool size, as well as the LFOM- and HFOM-PhytOC fractions. The LFOM- and HFOM-PhytOC concentrations were positively correlated with soil organic C concentrations. The HFOM-PhytOC concentration was positively correlated with that of water-soluble silicon. We conclude that the increasing bamboo plantation age will promote PhytOC storage in the bulk soil and physical fractions in subtropical China. Management practices that increase PhytOC input and decrease PhytOC output should be developed in the future to increase PhytOC storage in bamboo plantations.

Soil nutrients play critical roles in regulating and improving the sustainable development of economic forests. Consequently, an elucidation of the spatial patterns and drivers of soil nutrients in these forests is fundamental to their management. For this study, we collected 314 composite soils at a 0–30 cm depth from a typical hickory plantation in Lin’an, Zhejiang Province, China. We determined the concentrations of macronutrients (i.e., soil organic carbon, available potassium, available phosphorus, available sulfur, and hydrolyzed nitrogen) and micronutrients (i.e., soil available boron, iron, manganese, zinc, and copper) of the soils. We employed random forest analysis to quantify the relative importance of factors affecting soil nutrients to predict the concentrations, which could then be extrapolated to the entire hickory region. Random forest models explained 43–80% of the variations in soil nutrient concentrations. The mean annual temperature, mean annual precipitation, and altitude were key predictors of soil macronutrient and micronutrient concentrations. Moreover, slope and parent material were important predictors of soil nutrients concentrations. Distinct spatial patterns of soil nutrient concentrations were driven by climate, parent material, and topography. Our study highlights the various environmental controls over soil macronutrient and micronutrient concentrations, which have significant implications for the management of soil nutrients in hickory plantations.

The target element concentration ratios of Zn–Cr–Sn–O(ZCTO) thin films with different sputtering parameters prepared by radio frequency (RF) magnetron sputtering were analyzed by picosecond laser-induced breakdown spectroscopy (PS-LIBS). PS-LIBS method was employed to measure the thickness of the thin film in the depth profile of the ZCTO sample. The measured value of PS-LIBS is 372 ± 53 nm, presenting a small error with the actual value. The band gap of ZCTO thin-film samples is closely associated with the content ratio of the Sn element, which increases as sputtering power and sputtering pressure increase. As illustrated by comparing the relationship between the value of energy-dispersive X-ray spectroscopy (EDS) and transmittance, the band gap of ZCTO films increases with the increasing Sn/Zn content ratio. This can be represented by the LIBS spectral line of the corresponding element. Then, the Sn/Zn ratio of the films prepared under different sputtering parameters was quantitatively analyzed. The calibration curve of a single sputtering variable was obtained, while the rapid quantitative analysis of the Sn/Zn ratio based on multiple sputtering variables was realized. Moreover, the rapid micro-analysis of ZCTO films by the picosecond laser-induced breakdown spectroscopy method was realized using this method.

Background: Soil nutrients play critical roles in regulating and improving the sustainable development of economic forests. Consequently, an elucidation of the spatial patterns and drivers of soil nutrients in these forests is fundamental to their management. For this study, we collected 314 composite soils at a 0-30 cm depth from a typical hickory plantation in Lin 'an, Zhejiang Province, China. We determined the concentrations of macronutrients (i.e., soil organic carbon, hydrolyzed nitrogen, available phosphorus, and available potassium) and micronutrients (i.e., iron, manganese, zinc, and copper.) of the soils. We employed random forest analysis to quantify the relative importance of soil-forming factors to predict the soil nutrient concentrations, which could then be extrapolated to the entire hickory region. Results: Random forest models explained 61%–88% of the variations in soil nutrient concentrations. The mean annual temperature and mean annual precipitation were the most important predictor of soil macronutrient and micronutrient concentrations. Moreover, parent material was another key predictor of soil available phosphorus and micronutrient concentrations. Mapping results demonstrated the importance of climate in controlling the spatial distribution of soil nutrient concentrations at finer scales, as well as the effect of parent material, topography, stand structure, and management measures of hickory plantations. Conclusions: Our study highlights the biotic factors, abiotic factors, and management factors control over soil macronutrient and micronutrient concentrations, which have significant implications for the sustainability of soil nutrients in forest plantations.

Forest conversion may affect the soil microbial community through impacts on soil properties. However, our understanding of the effects on the soil bacterial community remains limited. The objective of this study was to understand the impacts of forest conversion of native broad-leaved species on soil bacterial structure and diversity. The phylogeny structure and diversity of the soil bacterial communities were compared among four forest types. We found that the soil total nitrogen (TN) and C:N ratios were significantly different between a mixed forest and other forest types. The native forest and mixed forest contained a higher relative abundance of Actinobacteria, Gammaproteobacteria, and Acidimicrobiia compared with the Chinese fir and Bamboo forests, but more unique operational taxonomic units (OTUs) were found in the Chinese fir and Bamboo forests. Soil bacteria in bamboo forest and Chinese fir forest showing a higher diversity but a lower total sequencing number than native forest and mixed forest. Among the soil properties, pH was an important variable that contributing to both soil bacterial communities and soil alpha diversities. Our work suggests that after a long-tern forest conversion, both land-use history and vegetation species strongly influence soil bacteria communities, and soil pH is a main factor that influences soil bacterial structure.

Pot experiment was conducted to investigate the effects of wood biochar (5%), bamboo biochar (5%), rice straw biochar (5%) and Chinese walnut shell biochar (5%) on growth, accumulation of heavy metals in moso bamboo, soil physical properties, and solubility of heavy metals in soil. The results revealed that dry weight of moso bamboo was significantly increased in treatments of wood biochar (5%), rice straw biochar (5%) and Chinese walnut shell biochar (5%) except bamboo biochar (5%). Application of straw biochar (5%) was most effective in enhancing plants biomass, with increase of 157%, 113% and 111% in leaves, roots and stems of moso bamboo. All treatments of biochar have significantly improved soil electrical conductivity with maximum increase of 360% compared to CK. In case of heavy metals accumulation, application of 5% bamboo biochar, straw biochar and Chinese walnut shell biochar has reduced Cu uptake in roots by 15%, 35% and 26%, respectively. The biochars have significantly reduced solubility of soil heavy metals with maximum reduction of 58.91 mg kg−1 and 10.59 mg kg−1 of Cu and Pb with application of rice straw biochar. It is concluded that dry weight of moso bamboo was significantly enhanced by all treatments of biochar except bamboo biochar.

Monitoring the temporal and spatial variation of soil properties is helpful to understand the evolution of soil properties and adjust the management method in time. Soil fertility evaluation is an urgent need to understand soil fertility level and prevent soil degradation. Here, we conducted an intensive field investigation in Chinese hickory (Carya cathayensis Sarg.) plantation to clarify the spatial and temporal variation of soil properties and its influencing factors, and to evaluate the change of soil fertility. The results showed that the soil pH and soil organic carbon (SOC) significantly increased from 2008 to 2018, while available nitrogen (AN) significantly decreased from 2008 to 2018. The semi-variance revealed that except available phosphorus (AP), the spatial dependencies of soil properties increased from 2008 to 2018. An increasing south-north gradient was found for soil AN, AP, available potassium (AK) and SOC and a decreasing south-north gradient was found for soil pH. The average soil fertility in the whole area was increased from 2008 to 2018. Our findings demonstrated that the changes of the management measures were the reason for the change of soil properties from 2008 to 2018. Therefore, rational fertilization strategies and sod cultivation are recommended to maintain the long-term development of the producing forest.

The use of exogenous silicon (Si) amendments, such as Si fertilizers and biochar, can effectively increase crop Si uptake and the formation of phytoliths, which are siliceous substances that are abundant in numerous plant species. Phytolith-occluded carbon (C) (PhytOC) accumulation in soil plays an important role in long-term soil organic C (SOC) storage. Nevertheless, the effects of both Si fertilizer and biochar application on PhytOC sequestration in forest plant-soil systems have not been studied. We investigated the impact of Si fertilizer and biochar applications on 1) the PhytOC pool size, the solubility of plant and soil phytoliths, and soil PhytOC in soil physical fractions (light (LFOM) and heavy fractions of organic matter (HFOM)) in Moso bamboo (Phyllostachys pubescens) forests; and 2) the relationships among plant and soil PhytOC concentrations and soil properties. We used a factorial design with three Si fertilizer application rates: 0 (S0), 225 (S1) and 450 (S2) kg Si ha−1, and two biochar application rates: 0 (B0) and 10 (B1) t ha−1. The concentrations of PhytOC in the bamboo plants and topsoil (0–10 cm) increased with increasing Si fertilizer addition, regardless of biochar application. Biochar addition increased the soil PhytOC pool size, as well as the LFOM- and HFOM-PhytOC fractions, regardless of Si fertilizer application. The Si fertilizer application increased or had no effect on soil phytolith solubility with or without biochar application, respectively. Soil PhytOC was correlated with the concentration of soil organic nitrogen (R2=0.32), SOC (R2=0.51), pH (R2=0.28), and available Si (R2=0.23). Furthermore, Si fertilizer application increased plant and soil PhytOC by increasing soil available Si. Moreover, biochar application increased soil PhytOC concentration in LFOM-PhytOC and the unstable fraction of PhytOC. We conclude that Si fertilizer and biochar application promoted PhytOC sequestration in the plant-soil system and changed its distribution in physical fractions in the Moso bamboo plantation in subtropical China.

Soil organic carbon (SOC) and total nitrogen (STN) are crucial soil quality indicators in a forest ecosystem. Their cycling processes and interactions have a key impact on the plants productivity, potential carbon sequestration and stability of the terrestrial ecosystem. In this study, soil profile samples (0–100 cm) were collected from 906 plots of typical subtropical forest in Zhejiang Province, southeastern China. Moran's I, geostatistics and geographic information system (GIS) techniques were used to study the vertical and horizontal heterogeneity of SOC, STN and C:N ratio. The results indicated that the contents of SOC and STN clearly decreased with the soil depth increasing (from 0 to 10 cm layer to 60–100 cm layer). The spatial distributions of SOC and STN were consistent with the topography, showing a decreasing trend from southwest to northeast of Zhejiang Province. The results of ANOVA and correlation analyses indicated that the dominant tree species, elevation and Normalized Difference Vegetation Index (NDVI) were the key factors affecting SOC and STN contents. For the total 0–100 cm soil layer, the mean densities of SOC and STN were 108.53 Mg ha−1 and 0.08 Mg ha−1, respectively. The total stocks of SOC and STN were 877.19 Tg and 84.42 Tg. Approximately 65% SOC and 45% STN were belonged to the upper 30 cm soil layer, which was strongly related to the actual soil thickness. The results could provide critical information for forestry and environmental management related to C and N accumulations in subtropical forests of China.

Spatial variation of regional soil organic carbon (SOC) stocks and the effects of environmental factors on SOC in forest soils play an essential part in modeling the global carbon cycle and climatic change. In this study, we analyzed topsoil samples (0–30 cm) from 838 plots in a typical subtropical forest of Zhejiang Province, southeastern China, using Moran's I, geostatistics and geographical information system (GIS) techniques. The results showed that the mean SOC density in the topsoils was 71.15 Mg ha−1 and the total storage in topsoils of Zhejiang Province was 0.47 Pg (Pg = 1015 g). The spatial distribution of SOC density based on kriging interpolation and local Moran's I hotspot analysis showed a decreasing trend from the southwest to northeast area, roughly in line with Zhejiang Province's topographic feature, as well as differences in land use, economic and social development. The results herein revealed that both dominant tree species and altitude (P

Soil organic carbon (SOC) is an important soil property relating to soil formation, structure, and water-holding capacity. Remote sensing has been used for predicting SOC but remains a challenge due to the complex and indirect relationship between SOC and remote sensing variables. In this research we explored the approaches of predicting SOC distribution in a hickory plantation region using random forest (RF) and geographically weighted regression (GWR) based on Landsat and ancillary data, analyzed SOC spatial distribution and dynamic change between 2008 and 2013 through a thresholding approach, and examined major factors that resulted in SOC degradation in the young and mature hickory plantations using a logistic regression. The results showed that RF outperformed GWR in the prediction of SOC and provided stable and reliable SOC predictions with root mean squared errors of 4.6 g kg−1 in 2008 and 4.4 g kg−1 in 2013. A large area of hickory plantation was experiencing SOC decrease. The analysis of major factors causing SOC degradation indicated that steep slope and high proportion of silt component in soil resulted in SOC decrease in the young hickory plantations, and high elevation, high proportion of silt component in the soil, and the increase of soil fraction in the ground cover led to SOC decrease in the mature hickory plantations. This research provides valuable approaches to spatially predict SOC and identify major factors driving SOC degradation, which will be useful for adopting better measures to improve management of hickory plantations.

Despite improving soil quality and reducing nitrogen (N) loss in paddy soil, replacing chemical fertilizer with organic fertilizer would significantly accelerate greenhouse gas emission in terms of methane (CH4). The application of slow-release fertilizer has been proposed an effective approach to control CH4 emissions, in addition to reducing N loss. Yet, the understanding of CH4 emissions from paddy fields with the additions of different fertilizers is still less known. Therefore, the effects of different fertilizer treatments, including chemical fertilizer treatment (CF), mixed chemical and organic fertilizer treatment (OF), biochar-based slow-release fertilizer treatment (SF), and no fertilizer control treatment (CK) on CH4 emissions and methanogenic community structure in paddy soils were investigated through a field experiment. Results showed that slow-release fertilizer addition significantly decreased CH4 emissions by 33.4%, during the whole rice growing season compared to those in OF. The cumulative CH4 emissions were in a significantly positive relation to soil NH4+-N. Slow-release fertilizer amendment decreased the relative abundances of Methanosarcina and Methanoregula and increased the relative abundances of hydrogenotrophic Methanocella and Rice Cluster I. Reduced CH4 emissions with slow-release fertilizer amendment might be mainly attributed to the different forms of N in the fertilizer and available potassium (K) in the paddy soil. Our findings produce novel insights into the application of slow-release fertilizer in controlling CH4 emissions from rice fields.

The antioxidation system and accumulation ability of Moso bamboo (Phyllostachys pubescens), which is a valuable remediation material with large biomass and rapid growth rate were studied in hydroponics and pot experiments. In hydroponics experiment, TBARS concentrations and SOD activities decreased with increase of Pb treatments. The activities of POD boost up with elevated Pb treatments, and reached peak level with application of 400μM Pb. Proline concentrations reduced with application of 20μM Pb and then enhanced consistently with application of 100 and 400μM Pb. The biomass of Moso bamboo improved with increase of Pb treatments upto 400mgkg-1, and then decreased with application of each additional increment of Pb in pot experiment. Application of 800mgkg-1 Pb showed significant increase of photosynthetic pigments, however, non significant variation was observed for other treatments. The Pb concentration in roots, stems and leaves attained 523mgkg-1, 303mgkg-1 and 222mgkg-1 respectively with application of 1600mgkg-1 Pb compared with control. Analysis of TEM-EDX revealed that Pb in cell was mostly concentrated in cytoplasm then in cell wall and followed by vacuole. It is concluded that Moso bamboo may be potential remediation species for phytoremediation in low Pb contaminated soils.

Plantation management practices could markedly change the sequestration of phytolith-occluded carbon (PhytOC) in plants and soils. However, for Moso bamboo (Phyllostachys pubescens) plantations, the effect of intensive plantation management (including fertilization, tillage, and removal of understory vegetation) on the accretion rate of PhytOC in the soil-plant system is much less understood than extensive management (without fertilization, tillage, and removal of understory vegetation). The objectives of this study were to investigate the effect of intensive and extensive management practices on the production, accumulation, and runoff of PhytOC and their distribution in physical fractions in Moso bamboo plantations. Our results showed that intensive management (1) increased PhytOC production mainly due to increased forest productivity, (2) increased PhytOC storage in the heavy fraction but decreased its storage in the light fraction of organic matter, resulting in the lack of effect on soil PhytOC storage, (3) increased the rate of dissolution of phytolith and the loss of PhytOC in runoff, and (4) promoted PhytOC sequestration in the soil-plant system, mostly in the plants, due to the greater rate of PhytOC production than the rate of loss. We conclude that intensive bamboo plantation management practices are beneficial to increasing long-term PhytOC sequestration in the soil-plant system.

To assess the effects of long-term intensive management on soil carbon cycle and microbial functional diversity, we sampled soil in Chinese hickory (Carya cathayensis Sarg.) stands managed intensively for 5, 10, 15, and 20 years, and in reference Chinese hickory&ndash, broad-leaved mixed forest (NMF) stands. We analyzed soil total organic carbon (TOC), microbial biomass carbon (MBC), and water-soluble organic carbon (WSOC) contents, applied 13C-nuclear magnetic resonance analysis for structural analysis, and determined microbial carbon source usage. TOC, MBC, and WSOC contents and the MBC to TOC ratios were lower in the intensively managed stands than in the NMF stands. The organic carbon pool in the stands managed intensively for twenty years was more stable, indicating that the easily degraded compounds had been decomposed. Diversity and evenness in carbon source usage by the microbial communities were lower in the stands managed intensively for 15 and 20 years. Based on carbon source usage, the longer the management time, the less similar the samples from the monospecific Chinese hickory stands were with the NMF samples, indicating that the microbial community compositions became more different with increased management time. The results call for changes in the management of the hickory stands to increase the soil carbon content and restore microbial diversity.

Glasses coated with a variety of thin films are extensively used. In the present study, copper oxide (CuO) thin films doped with aluminum (Al) or cobalt (Co) were prepared on the surface of soda lime glass substrates by radio-frequency magnetron sputtering deposition. The variation of the sputtering time resulted in the alteration of the composition of the films that caused changes in their optical properties as observed by energy dispersive X-ray spectroscopy (EDS) and optical transmission spectroscopy, respectively. In addition, laser-induced breakdown spectroscopy analysis (LIBS) was used to achieve rapid qualitative and quantitative analyses of the doping elements in the CuO thin films. The elemental emission intensity ratios of Al/Cu in CuO-Al thin films and Co/Cu in CuO-Co thin films obtained by LIBS was employed to assess the optical properties of the coated glass samples. Overall, the results revealed that the LIBS technique allows to efficiently determine the elemental composition of doped CuO thin films deposited by RF magnetron sputtering and to simultaneously assess the corresponding optical properties of thin films.

Root-associated fungal communities play a key role in plant productivity and soil processes in forest ecosystems. However, how diversity and composition of root-associated fungi change with forest development and their linkage with soil enzyme activities remain largely unknown. We characterized the root-associated fungal communities, plant and soil properties, and extracellular enzyme activities along a chronosequence spanning young (15 years old) to over-mature (63 years old) Pinus massoniana forest development stages. Our results showed that P. massoniana roots harbored diverse root-associated fungal communities and they varied with forest development. Near-mature (36 years old) forest stands had the lowest alpha-diversity but higher relative abundances of ericoid mycorrhizal and activities of enzymes involved in C, N and P acquisition. The relative abundances of ectomycorrhizal fungi and endophyte were higher in middle-age (24 years old) and mature stands (45 years old), whereas the relative abundance of ericoid mycorrhizal fungi was highest in the near-mature stand. Soil pH, soil C:P and N:P ratios were important factors shaping the diversity and composition of root-associated fungal communities. Structural equation modeling indicated that changes in the community composition, but not richness of root-associated fungi, had significant correlations with soil enzymatic C:N and N:P stoichiometry. In conclusion, this study suggests that different stand development stages exhibit distinct diversity and composition of root-associated fungal communities, which affecting soil functions in terms of enzymatic activity.

Organic carbon (C) occluded in phytolith (PhytOC) is stable in the soil for millennia and can be an important contributor to long-term C storage in forest ecosystems. In order to understand the effect of parent material and vegetation type on the production of PhytOC in plant litter in subtropical forests in China, we investigated the PhytOC concentration and stock in plant litter in four forest types, moso bamboo ( Phyllostachys edulis Moso), Chinese-fir ( Cunninghamia lanceolata ), evergreen broadleaf and mixed conifer-broadleaf forests, established on three parent materials (rhyolite, sandy shale and tuff). This study showed that: 1) both parent material and forest type significantly affected phytolith concentrations in litter, and there was a significant interaction between parent material and forest type. Plant litter in the moso bamboo forest developed on rhyolite and tuff had the highest phytolith concentrations followed by moso bamboo forest on sandy shale; 2) forest type but not parent material affected PhytOC concentrations in litter, with the highest in the moso bamboo forest; 3) both parent material and forest type significantly affected PhytOC stock in litter, without a significant interaction between the two factors. The moso bamboo forest had the highest PhytOC stock in its litter; and 4) the PhytOC stock returned to the soil in moso bamboo, Chinese-fir, evergreen broad-leaf and mixed coniferous forests was (mean ± SD) 14.66 ± 4.69, 2.87 ± 2.19, 6.22 ± 2.46 and 4.84 ± 1.82 kg ha −1 , respectively. Considering the area of the four respective forest types, the amount of C that can be entered into the soil in the form of PhytOC in litter was 2.08 × 10 5 , 1.19 × 10 5 , 5.68 × 10 5 and 2.75 × 10 4 t CO 2 -e, respectively, and therefore it indicates a great potential in long-term C storage.

Phytolith-occluded carbon (PhytOC) with high resistance against decomposition is an important carbon (C) sink in many ecosystems. This study compared concentrations of phytolith in plants and the PhytOC production of seven sympodial bamboo species in southern China, aiming to provide the information for the managed bamboo plantation and selection of bamboo species to maximize phytolith C sequestration. Leaf litters and living leaves of seven sympodial bamboo species were collected from the field sites. Concentrations of phytoliths, silicon (Si), and PhytOC in leaf litters and living leaves were measured. Carbon sequestration as PhytOC was estimated. There was a considerable variation in the PhytOC concentrations in the leaf litters and living leaves among the seven bamboo species. The mean concentrations of PhytOC ranged from 3.4 to 6.9 g kg(-1) in leaf litters and from 1.6 to 5.9 g kg(-1) in living leaves, with the PhytOC production rates ranging from 5.7 to 52.3 kg e-CO2 ha(-1) year(-1) as leaf litters. Dendrocalamopsis oldhami (Munro) Keng f. had the highest PhytOC production rate. Based on a bio-sequestration rate of 52.3 kg e-CO2 ha(-1) year(-1), we estimated that the current 8 × 10(5) ha of sympodial bamboo stands in China could potentially acquire 4.2 × 10(4) t e-CO2 yearly via phytolith carbon. Furthermore, the seven sympodial bamboo species stored 5.38 × 10(5) t e-CO2 as PhytOC in living leaves and leaf litters in China. It is concluded that sympodial bamboos make a significant contribution to C sequestration and that to maximize the PhytOC accumulation, the bamboo species with the highest PhytOC production rate should be selected for plantation.

Moso bamboo (Phyllostachys pubescens (Pradelle) Mazel ex J.Houz.) is recognized as a potential phytoremediation plant due to its huge biomass and high tolerance to environmental stresses. The objectives of this study were to investigate mechanism related to cadmium (Cd) tolerance and to evaluate Cd accumulation capacity of moso bamboo. The results of the pot experiment showed that Cd accumulation by bamboo increased with increasing the Cd levels in soil and the values in stem ranged from 28.51 to 132.13 mg kg(-1). Meanwhile chlorophyll in leaves and total biomass showed a decreasing trend. The bioaccumulation factors (BAF) for roots and stem in all the treatments were more than 1.0 and the translocation factor (TF) ranged from 0.70 to 1.06. In hydroponics experiment, the concentrations of malondialdehyde (MDA) in the leaves were significantly increased in Cd treated plants as compared with control. The activities of superoxide dismutase (SOD) and peroxidase (POD) were enhanced at initial stage and then decreased consistently with the increase of Cd addition. The proline concentrations were also increased due to the presence of Cd, particularly at 25 μM Cd treatment. According to TEM-EDX analysis, the cytoplasm was the main site for accumulation of Cd in moso bamboo. On the basis of overall results, it is suggested that moso bamboo could be successfully used for the remediation of low Cd (no more than 5 mg kg(-1)) contaminated soils.

Al-In-Sn-O (AITO) thin film refers to a novel wide-bandgap transparent conductive material, which is formed by doping the aluminum element into In-Sn-O material. It is of promising application in deep ultraviolet optoelectronic devices. A l / A l + I n + S n and S n / A l + I n + S n are capable of impacting the optical and electrical properties of AITO thin film. Three groups of AITO thin film samples with different sputtering powers, sputtering pressures, and sputtering times were prepared with magnetron sputtering. The concentration ratio of A l / A l + I n + S n and S n / A l + I n + S n in AITO samples was quantitatively analyzed with laser-induced breakdown spectroscopy (LIBS) technology. A single calibration curve was drawn based on the sputtering parameters of each group, and the comprehensive calibration curves of two concentration ratios under any sputtering parameters were plotted. The accuracy of the comprehensive calibration curve was determined with samples prepared under random sputtering parameters, and the energy dispersive x-ray spectroscopy analysis results were compared with the LIBS technical analysis results. The relative error was less than 5%, so the LIBS technical analysis was demonstrated to be accurate. By building the comprehensive calibration curve, a novel method to conduct rapid online analysis of AITO thin films and timely determination of photoelectrical properties is presented, and the new application of LIBS technology is developed in thin film semiconductor materials.

Chinese hickory (Carya cathayensis Sarg.) is a famous woody nut in China. Currently, there is an increasing concern related to the soil heavy metal pollution in Chinese hickory plantations. In this study, a total of 188 soil samples were collected from Lin’an city, a typical Chinese hickory production area. The results showed that the average background concentrations of Cd, Cu, Zn, Pb, Ni and Cr in soils were 0.37, 40.76, 87.61, 30.10, 28.33 and 56.57 mg kg−1, respectively. The Cd and Pb concentrations in Chinese hickory plantation soils had strong variability coefficients of 186.49% and 95.42%, respectively. Compared with the background values in Zhejiang province, the heavy metals were enriched in the plantation soils. The accumulation ratio followed the order of Cu > Cd > Pb > Ni > Zn > Cr. Part of the study area was seriously contaminated by Cd and Cu, as 31.38% of soil Cd and Cu samples exceeded the second grade standardized value of Environmental Quality Standards of Soils (EQSS). The soils in our study area generally reached a moderate ecological risk, as its average RI value reached 103. Moran’s I and Kriging interpolation results revealed that all the studied heavy metals in soils had clear spatial distribution patterns. The high values of soil heavy metals (except Pb) were mainly distributed in the localities closest to the mine area. The apportionment of heavy metal pollution sources showed that the Cu, Ni and Cr in soils were mainly related to mining activities, Pb was closely related to fertilizer application, Cd and Zn were related to both. The heavy metals in soils may pose a potential threat to local ecosystem and human health. Our results implied that soil heavy metals should be tested, and risk-based management should be performed in the economic plantations in China. These maps could provide useful information for forestry and environmental management.

Outliers are classified as global outliers and spatial outliers. Up to now, there is little information about the outliers especially the spatial outliers and their influence on the spatial structure modeling of soil properties. A total of 537 soil samples were collected based on a 30 × 30 m grid in a permanent dairy farm in southeast Ireland. Graphic methods of histogram and box plot combined with Moran’s I were applied to detect the outliers of soil phosphorus (P). Sixteen outliers (5 global outliers and 11 spatial outliers) of soil P were found in the study area. Compared to the raw data, the data with global outliers excluded always had the larger global Moran’s I value indicating a stronger spatial autocorrelation. Clear spatial clusters (High–High and Low–Low clusters) were observed based on local Moran’s I. The High–High spatial clusters were located around the main farm yard and near the traffic route due to more intensive management by farmers. The Low–Low spatial clusters were mainly close to the river. For these areas, P fertilizer or slurry should be applied for healthy grass growth. The dataset with outliers excluded had a reliable semi-variogram model with a low nugget/sill ratio (32.4 %), which was closed to its corresponding transformed data (30.5 %). The cross-validation results revealed that the dataset without outliers had the strongest linear regression model (r = 0.768), indicating that the outliers played an important role in the spatial structure modeling.

Phytolith-occluded organic carbon (PhytOC) is an important long-term (up to several thousand years) terrestrial carbon (C) fraction in forest ecosystems. The objectives of this study were to (i) investigate the spatial distribution of PhytOC in Lei bamboo (Phyllostachys praecox C.D. Chu & C.S. Chao.) forests under intensive management (mulching and fertilization) and (ii) assess the role of PhytOC in C sequestration in a Lei bamboo stand and across subtropical China. Phytolith concentrations in Lei bamboo plant components were (P < 0.05) in the following order: rhizome ≈ stump > leaf ≈ branch > culm. The distribution of PhytOC in bamboo leaves, branches, culms, rhizomes, and stumps was 22.2%, 12.1%, 16.1%, 15.9%, and 33.7%, respectively. The PhytOC stock was in the following order (P < 0.05): soil (9361 kg C·ha−1) > mulching materials (197.5 kg C·ha−1) > belowground plant parts (13.0 kg C·ha−1) ≈ aboveground plant parts (12.8 kg C·ha−1) ≈ litterfall (11.3 kg C·ha−1). The PhytOC accretion rate in the vegetation in the Lei bamboo stand was 19.4 kg C·ha−1·year−1, equivalent to 71 kg CO2-eq·ha−1·year−1. The soil PhytOC stock decreased markedly with depth and had an accretion rate of 325 kg C·ha−1·year−1 for the 0–60 cm soil layer. Based on a PhytOC accretion rate of 0.795 Mg CO2-eq·ha−1·year−1, PhytOC accretion rate in the 2.62 × 106 ha of Lei bamboo stands in southern China is estimated to be 2.08 × 106 Mg CO2-eq·year−1. In conclusion, intensively managed Lei bamboo stands have a large potential in long-term C sequestration in the form of PhytOC, and the PhytOC stock belowground should not be ignored due to its contribution to the ecosystem level PhytOC stock.

A hydroponics experiment was aimed at identifying the lead (Pb) tolerance and phytoremediation potential of Moso bamboo (Phyllostachys pubescens) seedlings grown under different Pb treatments. Experimental results indicated that at the highest Pb concentration (400 μmol/L), the growth of bamboo seedlings was inhibited and Pb concentrations in leaves, stems, and roots reached the maximum of 148.8, 482.2, and 4282.8 mg/kg, respectively. Scanning electron microscopy revealed that the excessive Pb caused decreased stomatal opening, formation of abundant inclusions in roots, and just a few inclusions in stems. The ultrastructural analysis using transmission electron microscopy revealed that the addition of excessive Pb caused abnormally shaped chloroplasts, disappearance of endoplasmic reticulum, shrinkage of nucleus and nucleolus, and loss of thylakoid membranes. Although ultrastructural analysis revealed some internal damage, even the plants exposed to 400 μmol/L Pb survived and no visual Pb toxicity symptoms such as necrosis and chlorosis were observed in these plants. Even at the highest Pb treatment, no significant difference was observed for the dry weight of stem compared with controls. It is suggested that use of Moso bamboo as an experimental material provides a new perspective for remediation of heavy metal contaminated soil owing to its high metal tolerance and greater biomass.

The effects of zinc (Zn) on seed germination and growth of Moso bamboo (Phyllostachys pubescens) were investigated. Under zinc stress, the seed germination rate did not show significant difference from that of the control. Hydroponics experiments indicated that Moso bamboo had a strong ability to accumulate Zn in the shoot and it reached its maximum value in the shoot at 100 μM Zn. The root Zn concentration ranged from 2,329.29 to 8,642.51 mg kg(-1), with the root Zn concentration at 10 μM Zn being 58.23 times that of the control. The root morphology parameters slightly increased at the lower Zn treatments, while growth restriction was evident at higher Zn treatments. Root ultrastructural studies revealed that the cell structure, root tips, and organelles were significantly changed under Zn stress as compared to those of the control. Some abnormalities were evident in the cell walls, vacuoles, mitochondria, plasmalemma, tonoplast, and xylem parenchyma of root cells. While Moso bamboo seems a suitable candidate for phytoremediation, its metal remediation ability should be further explored in future investigations.

The effect of plant invasion on soil microbial communities in various ecosystems has increasingly become the focus of research over the last decade. Moso bamboo (Phyllostachys edulis) invasion of native forests in Tianmushan National Nature Reserve located in southeastern China has resulted in greatly decreased biodiversity of plants and birds. We combined three different microbial community techniques (Biolog, cellular fatty acids, and 16S-PCR–DGGE) to examine whether changes in the overstory of plant taxa, or any associated environmental changes, modified soil microbial communities. Three types of forests were examined: mono-bamboo forest, mixed forest of bamboo and broadleaf, and native broadleaf forest. The fatty acid and DGGE results showed that bamboo invasion of the native forest influenced soil community structure and increased microbial biomass and taxonomic diversity despite decreased plant diversity. The Biolog results indicated no change in microbial functional diversity as a result of bamboo invasion. Evidence from bacterial PCR–DGGE suggested that bamboo stimulated the growth of otherwise undetected soil bacterial species. Overall, the results indicate that bamboo invasion may significantly affect associated soil microbial communities.

Changes in land-use can markedly influence soil carbon (C) and nitrogen (N) pools, and consequently C sequestration and soil fertility. The objective of this study was to investigate the effects of converting native shrub forests (NSF) to Chinese chestnut (Castanea mollissima Blume) plantations (CP) and the subsequent long-term intensive management (including chemical fertilizer application, deep tillage and understory vegetation control) on soil C and N pool sizes and the chemical composition of soil organic C (SOC). We studied SOC and total N (TN) storage, water soluble organic C (WSOC), hot-water soluble organic C (HWSOC), microbial biomass C (MBC), readily oxidizable C (ROC), NH 4 + –N, NO 3 - –N, water soluble organic N (WSON), microbial biomass N (MBN), and chemical composition of SOC determined by the 13C-nuclear magnetic resonance (NMR) technique in the soils of NSF and CP with 5, 10, and 20 years of intensive management. Our results showed that conversion of NSF to CP decreased SOC storage and concentrations of WSOC, HWOC, MBC, ROC, WSON, and MBN (P NH 4 + –N and NO 3 - –N (P

Exponential fertilization has been regarded as an important technique for improving seedling quality at the initial plant-growth stage. In our study, containerized one-year-old Chinese fir (Cunninghamia lanceolata (Lamb.) Hook) rooted cuttings were reared at four nitrogen (N) fertilizer levels (0, 0.5, 1.0, 2.0 g cutting&minus, 1 season&minus, 1) under two topdressing methods (conventional and exponential) for a 210-day greenhouse rotation to evaluate growth and nutrient loading capacity of seedlings. N fertilizer was applied 20 times at an interval of 10 days during the study period. The results indicated that the schedule and rate of fertilization significantly affected the height, ground diameter, and biomass of Chinese fir rooted cuttings. The nitrogen concentration of different plant organs followed the order of leaves &gt, root &gt, stem. Compared to the CK, the N concentrations in root, stem, and leaves increased by 39.6%, 16.6%, and 41.1% in the conventional fertilizer treatment, and by 22.6% to 81.4%, 27.3% to 152.6%, and 73.6% to 135.5% in exponential fertilization treatments, respectively. The N concentrations of root, stem, and leaves of Chinese fir rooted cuttings under EF2 (1.0 N g cutting&minus, 1) were significantly higher than that of conventional fertilization (p &lt, 0.05). However, there was no significant difference of phosphorus and potassium concentrations among different plant organs. Steady-state nutrition and superior growth performance were achieved by rooted cuttings fertilized exponentially at the rate of 1.0 g cutting&minus, 1 yielding (EF2).

Background and aims The impact of understory vegetation control or replacement with selected plant species, which are common forest plantation management practices, on soil C pool and greenhouse gas (GHG, including CO2, CH4 and N2O) emissions are poorly understood. The objective of this paper was to investigate the effects of understory vegetation management on the dynamics of soil GHG emissions and labile C pools in an intensively managed Chinese chestnut (Castanea mollissima Blume) plantation in subtropical China.

Intensive forest management practices, such as fertilization, tillage, and understory removal, could markedly change the soil organic carbon (SOC) stock and labile organic carbon (C) pools. However, the combined effects of such intensive management practices on the quantity and quality of soil SOC in bamboo forests are poorly understood. The objectives of this study were to investigate the impact of long-term intensive management practices, including inorganic fertilizer application, tillage, and understory removal, on total and labile SOC pools and chemical composition of SOC in Moso bamboo (Phyllostachys pubescens) forests and to explore relationships between different soil organic C forms. We used a chronosequence approach (consisting of Moso bamboo forests with 0, 5, 10, 20, 30 years of intensive management) to examine the effects of long-term intensive management on SOC storage, water soluble organic C (WSOC), hot-water soluble organic C (HWSOC), microbial biomass C (MBC), readily oxidizable C (ROC), and SOC chemistry. Our results showed that SOC stock and concentrations of WSOC, HWSOC, MBC, and ROC decreased with increasing duration under intensive management. For the chemical composition of SOC, the contents of alkyl C and carbonyl C and the alkyl C to O-alkyl C (A/O-A) ratio increased, while the contents of O-alkyl C and aromatic C and aromaticity decreased as duration under intensive management increased, suggesting that long-term intensive management changed the SOC chemical composition. Soil MBC was negatively correlated with both alkyl C content and the A/O-A ratio (P < 0.01 for both), and was positively correlated with O-alkyl content (P < 0.01), indicating that soil microbial population size may be partly dependent on the chemical composition of SOC. In addition, O-alkyl C content was correlated with concentrations of WSOC (P < 0.05), HWSOC (P < 0.01), and ROC (P < 0.01), which implied that O-alkyl C might be the main C component of WSOC, HWSOC, and ROC. We conclude that long-term intensive management reduced the total and labile SOC stocks in bamboo forests and alternative management regimes should be developed to increase C sequestration of soils in intensively managed Moso bamboo forests in subtropical China.

Sewage effluents are increasingly used for farmland irrigation worldwide. This practice makes N losses via gaseous forms and leaching process more complex. Twelve repacked lysimeters with 90 cm height and 25 cm inner diameter were used for comprehensively determining am- monia (NH3) and nitrousoxide(N2O) emissionsand N leachinglossesina rice-wheat cropping system irrigated with N-rich wastewater from a live- stock pond. There were four irrigation treatments with three replications: wastewater with high N concentration (HW), wastewater with medium N concentration (MW, one-half dilution of wastewater of HW), wastewater with low N concentration (LW, one-fourth dilution of wastewater of HW), and ultrapure water control (CK). All treatments received equal amounts of total N (225 kg N ha �1 in the riceseasonand 150kgNha �1 in thewheat season) by balancing with commercial N fertilizer. The wastewater was provento be as effective ascommercialN fertilizer to achieve the optimum crop yields when applied in an appropriate amount. The NH3 emission, N leaching, and N2O emission losses accounted for 16.2 to 19.8%, 4.6 to 6.4%, and 0.26 to 0.35% of the total N applied in the rice season, respec- tively, whereas they were 2.7 to 3.3%, 2.2 to 2.8%, and 0.77 to 1.0% in the wheat season. Irrigating with wastewater did not change the NH3 emission flux pattern after N fertilizer (urea) was applied, but it boosted the NH3 emission flux to a certain extent in the rice season, especially for the MW treatment, which was mainly attributed to the high ammonium con- tent and pH of the flood surface water resulting from a combined effect of wastewater and urea-N application. In addition, N-rich wastewater irri- gation did not significantly increase N2O emission and N leaching when the total N inputs and the amount of irrigation were the same.

Forest ecosystems play an important role in sequestering carbon in their biomass and soils. Moso bamboo plantations, as a special forest type, are mainly distributed in southern China. There is little information about the carbon storage in moso bamboo plantations, it is now important to better understand the moso bamboo’s carbon sequestration. The main objectives of this study were to investigate the spatial variation of aboveground biomass carbon (AGC) and soil organic carbon (SOC) in moso bamboo plantations and to compare carbon storage in moso bamboo plantations under different management options. A total of 73 moso bamboo plots were selected in Anji County, which is a famous “bamboo town” in northwest Zhejiang province, China. The diameter at breast height and the age of each moso bamboo in the selected plots were measured in order to calculate the AGC. SOC was analyzed using sulfuric acid–potassium dichromate solution. One-way ANOVA was applied to analyze the significant difference of AGC and SOC under different management options. Geostatistics and geographical information were used to study the spatial dependence characteristics of AGC and SOC. The AGC values were very variable, ranging from 9.92 to 38.70 Mg ha−1, with an average of 20.85 Mg ha−1. The SOC values were from 34.8 to 176.17 Mg ha−1. Both the AGC and SOC values were followed normal distributions. Moso bamboo plantations contributed about 16.5 % of total forest biomass carbon in Zhejiang Province, indicating its important influence on regional carbon budget. Geostatistical analysis revealed that the AGC had moderate spatial autocorrelation. A nested model (a spherical model with a Gaussian model) was chosen to describe the variogram. Spatial patterns for AGC were found in Anji County, with relatively high AGC values were found in the southwestern part of Anji County, and low values were located in the eastern and central parts of the county. While no clear spatial autocorrelation trend was observed in the semivariogram of SOC, indicating a random distribution pattern for SOC in the study area. Meanwhile, the Pearson’s correlation between AGC and SOC in bamboo plantation was weak (r = 0.064, p = 0.496), due to moso bamboo’s special growth process and different management options by human beings. In this study, moderate spatial dependency was found for AGC, while the spatial autocorrelation of SOC was poor. In moso bamboo forest ecosystem, SOC was mainly stored at the top 40 cm layer. Management options were proved to be an important factor for carbon sequestration. Extensive management is an efficient way to increase carbon stock, compared to moderate and intensive management. With the rapid increase of plantation area, moso bamboo ecosystem will continue to play an important role in regional carbon budget.

Moso bamboo (Phyllostachys pubescens) has great potential as phytoremediation material in soil contaminated by heavy metals. A hydroponics experiment was conducted to determine organic acid compounds of root exudates of lead- (Pb), zinc- (Zn), copper- (Cu), and cadmium (Cd)-tolerant of Moso bamboo. Plants were grown in nutrients solution which included Pb, Zn, Cu, and Cd applied as Pb(NO3)2 (200 μM), ZnSO4·7H2O (100 μM), CuSO4·5H2O (25 μM), and CdCl2 (10 μM), respectively. Oxalic acid and malic acid were detected in all treatments. Lactic acid was observed in Cu, Cd, and control treatments. The oxalic was the main organic acid exudated by Moso bamboo. In the sand culture experiment, the Moso bamboo significantly activated carbonate heavy metals under activation of roots. The concentration of water-soluble metals (except Pb) in sand were significantly increased as compared with control. Organic acids (1 mM mixed) were used due to its effect on the soil adsorption of heavy metals. After adding mixed organic acids, the Cu and Zn sorption capacity in soils was decreased markedly compared with enhanced Pb and Cd sorption capacity in soils. The sorption was analyzed using Langmuir and Freundlich equations with R 2 values that ranged from 0.956 to 0.999 and 0.919 to 0.997, respectively.

Purpose Heavy winter mulch treatments are commonly practiced in Phyllostachys praecox bamboo forests to increase bamboo shoot production in early spring in subtropical China. The aim of this study was to quantify the chemical behaviour of the mulching materials and the immediate response of soil carbon (C) to the heavy winter mulch treatments.

Estimation of soil loss or evaluation of soil erosion risk has been an active research topic and has had much attention in the past three decades. The application of Revised Universal Soil Loss Equation (RUSLE) in large areas is a challenge because of data availability and quality. The RUSLE model was used in this article to evaluate soil erosion risk based on soil samples, a soil type map, digital elevation model (DEM) data, and Landsat Thematic Mapper (TM) images. Multiple regression analysis was used in order to identify major factors that influence the risks of soil erosion. A regression model based on DEM-derived slope gradient and TM-derived fractional soil and vegetation images was developed to map soil erosion risk distribution in a forest ecosystem in Zhejiang, China. The method that was developed has the potential to quickly examine the spatial distribution of the risk of soil erosion. This article provides a new insight for the evaluation of soil erosion risks in forest ecosystems with the integration of remote sensing and geographic information systems (GIS).